**WARNING - The following story contains graphic material that may be unsuitable or disturbing to some readers. 9NEWS is choosing to be very general in the description of what was said in open court by the witnesses because the testimony given in open court was extremely graphic.**

PROSECUTION CALLS ITS FIRST WITNESS

The first witness for the prosecution took the stand on Friday to testify against Austin Sigg, 17. Westminster Police's Louis Lopez is the lead detective on the case against Sigg.

During his testimony, he outlined the Jessica Ridgeway case.

He said Jessica usually walked to school with her classmate Jeremy. That day, Jessica called Jeremy's dad to make sure he was walking to school that day due to some bad weather. Jeremy's dad said Jeremy was going to walk to school that day. Jessica never showed up to walk with him.

EVIDENCE STARTS TO ROLL IN

On Oct. 7, Lopez says they found the backpack connected to Jessica. Inside the backpack, they found boots, prescription glasses, jeans, winter gloves, a tie-dyed T-shirt, a water bottle and Jessica's underwear. According to Lopez, police found "touch DNA" inside her underwear. That DNA matched a sample taken from the Ketner Lake incident where a jogger was attacked and the suspect was never found.

Lopez also recalled the day Jessica's body was discovered. Workers picking up trash found the torso of a small child. There were no arms, no legs and no head attached to the torso. They were not sure if it was a girl or a boy. DNA found on Jessica's torso was compared to the DNA found on the water bottle from the backpack. It was a match.

TIPSTERS START CALLING POLICE

On Oct. 19, investigators received a tip from a neighbor saying she was Sigg's neighbor.

The tipster said she saw the photo of the cross released by police as possibly connected to the case. The tipster claimed she saw Sigg wearing crosses often and that he was "obsessed with death." Later that day, the FBI went to Sigg's house to collect DNA evidence. On Oct. 21, another DNA sample was taken.

On Oct. 23, Lopez said Sigg's mother Mindy called a tipline at 7:30 p.m. Mindy reportedly said Austin admitted to killing Ridgeway and attacking the Ketner Lake jogger.

Police went to Sigg's home to investigate. They found remains in the crawl space of the house. The cause of death according to the coroner was asphyxiation.

Lopez pointed out the Siggs and the Ridgeways did not know each other.

SEX ASSAULT NURSE TESTIFIES

The second witness was Anissa Jones. Jones is a sexual assault nurse examiner.

Jones testified about her forensic exam of Jessica's remains. She said Jessica's body had multiple bruises and lacerations on it.

"I believe there was some sort of penetration that occurred," Jones testified.

The defense team clarified that no semen or sperm was discovered during the exam.

During Jones' testimony, Jessica's mother kept closing her eyes. It was visibly difficult for her to hear the testimony.

DETECTIVE CLARIFIES THE CHILD-PORN CHARGES

The third witness called by the prosecution this week was a detective who talked about the child porn they found.

Just half-an-hour before the hearing was set to start on Monday, 9NEWS learned three additional charges of "sexual exploitation of a child" were added against the suspect.

Detective Chris Pyler works for the Westminster Police Department in its Crimes Against Children/Internet Crimes division. Pyler testified that police confiscated a laptop and two hard drives from a computer tower from Sigg's home.

All three hard drives were taken to the sheriff's office lab in Boulder to be examined. All three had pictures on them of underage boys and girls exposing their private parts.

Pyler addressed the child porn accusations. He said detectives found a hard drive and a laptop that had pornographic photos of children on it.

Pyler testified to examining what he called a "rape fantasy video" where in a simulation a man walks into a woman's apartment, comes up from behind her, puts a rag on her face and renders her unconscious."

The defense asked Pyler if he had identified how and where the computers were purchased, asking also if anyone in the home was allowed to use them. 9NEWS Crime and Justice Reporter Anastasiya Bolton says this could have been asked in an attempt to allude that anyone had access to the hard drives and could possibly viewed the material.

The detective testified he didn't check if the computers were purchased new or from a third party. He said it appeared that anyone inside the home would have access to the machines.

SIGG DENIES SEXUAL ASSAULT; CONFESSES TO MOTHER

On Friday afternoon, Westminster Police Detective A.C. Stutson testified on what Austin Sigg's mother told him about the confession. Sigg told his mother that he did not rape Jessica.

He said he grabbed Jessica as she walked by his car. He put zip ties around her arms and legs and drove around with her.

Sigg then told his mother he tried to choke Jessica with zip ties but when that did not work he used his hands. He then said he dismembered Jessica in a bathtub using a saw from the garage.

Stutson also testified that while at Sigg's home on Oct. 23, Sigg asked him if "it would bring comfort to Jessica Ridgeway's family if he were to be held accountable."

He also inquired how long it would take for his DNA results to be processed. Police took DNA from Sigg twice on Oct. 19 and 21.

Stutson also testified that Sigg asked police that whoever was going to take bags with body parts out of the crawl space would do it without his mom watching. He was concerned, the detective testified, his mother would forever have those images in her head.

"I plan to plead guilty to this," Stutson told the judge Austin Sigg said to him.

Sigg also asked about the court process and sentencing.

Stutson also testified Sigg told police "he knew what he did was wrong and he wanted to make up for it."

911 CALL

The Prosecution also played part of the 911 call made by Mindy Sigg. A portion of the called included the following transcription:

MINDY SIGG: Come to my house. My son wants to turn himself in for Jessica Ridgeway's murder. He just confessed to killing her. He did it. He gave the details. He remains in my house.DISPATCHER: How old is he?MINDY: 17DISPATCHER: What's his name? Austin Sigg?MINDY: He did it. He wanted me to call.

The dispatcher then asks to speak to Austin Sigg. He gets on the phone.

DISPATCHER: How are you feeling?AUSTIN SIGG: I don't know why you're asking me these questions.AUSTIN: I murdered Jessica Ridgeway. I have proof that I did. You should send a squad here. [She's] in the crawl space.DISPATCHER: Did you know Jessica before this?AUSTIN: No I did not.DISPATCHER: Do you have any weapons in your home?AUSTIN: Yes, I plan to use none of them. I have knives in my room [but] there will be no resistance what so ever.

The dispatcher asks if he has any criminal record.

AUSTIN: The only other thing I've done is the Ketner Lake incident. The only other criminal history is a speeding ticket.

Lynch testified about his interview with the Ketner Lake victim in May of 2012. He told the court the victim said a man attacked her from behind with a red rag that smelled of gas, she felt dizzy and light headed. They fought and she was able to run away.

The clothing of the Ketner Lake victim was tested for DNA and it matched the DNA found on the bottle in Jessica Ridgeway's backpack.

The victim did identify Austin Sigg in a photo lineup as her attacker, Lynch testified in court.

The woman told police she was never touched in private places and most of the fighting she did with her attacker was described as shoving.

The judge then dismissed the count of attempted sex assault associated with the Ketner Lake incident.

She said she arrived home from work one day and Austin was on her bed. He was not feeling well, Lynch testified.

Sigg told her he needed to tell her something. Austin told Mindy Sigg "I'm a monster." Mindy asked "Is this reference to Jessica?" Austin replied "Yes," according to Lynch.

Lynch testified Mindy asked Austin about the girl in the park, he said he was responsible for the incident.

He told his mother he used the chloroform he made from a recipe on the internet. Mindy also told the detective she "caught Austin looking at porn" when he was around 12 to 13 years old. She took him to a Christian counselor to talk about it.

When Mindy told him he was going to jail, Lynch testified, Austin said his "life was over."

COURT PROCEEDINGS DURING THE PRELIMINARY HEARING

On the counts against Sigg, counts 12 and 13 were dismissed on Friday. Those counts were connected to the Ketner Lake attack.

The preliminary hearing is done. The arraignment date will is set for March 12 at 1:30 p.m. Sigg will plead during his arraignment.

OPENING THE PRELIMINARY HEARING TO MEDIA

The Colorado Supreme Court overturned a judge's decision to close the hearing.

In an opinion issued Thursday, justices sided with media organizations who argued that the judge failed to show that holding the hearing in public would jeopardize Austin Sigg's right to a fair trial or consider other ways to protect Sigg's rights without shutting out the public.

Judge Stephen Munsinger in December said he closed the hearing because he wanted to ensure a fair trial and to protect the privacy of victims and their families.